PROTOPLASM A MINUTE FOAM 219 



allowed, at this opportunity, to refer also to the fact that a 

 physicist such as Quincke names bodies of this nature " foams " 

 without hesitation, when they are composed of two fluids. I 

 point this out because, as is well known, it has been brought 

 forward against me from several sides that I make an incorrect 

 use of the word foam ; that is to say, that the foams described 

 by me should more correctly be termed emulsions of two fluids. 



5. The Structure of Protoplasm is Alveolar or Honeycombed 

 (Foam-like) 



After having set forth briefly the various views held upon 

 the structural relations of protoplasm, we must finally pass 

 on to place upon a stronger basis the opinion which I have 

 represented for some time, and which I am seeking to 

 establish more firmly by means of the present investigation. 



This view culminates essentially, to express myself as 

 briefly as possible, in this, that protoplasm has a structure 

 such as we have seen and thoroughly studied in the 

 artificially produced drops of oil-lather, that is to say, it 

 has a foam-like structure. 



It will therefore be my first task to set forth the reasons 

 which make it probable or certain that the spongy frame- 

 work commonly assumed to exist, or fibrils connected in a 

 net-like manner, cannot be present in protoplasm. For 

 there is no need of any special discussion to show that the 

 decision between these two possibilities cannot be reached 

 from the microscopic image alone. The minuteness of the 

 structures renders it impossible to make out off-hand whether 

 the reticular appearance observed corresponds to a spongy 

 framework or an alveolar meshwork, since the microscopic 

 image, as has been said, must in such minute structures be 

 the same in both cases. 



expressed before by physicists. For instance, Guthrie (1875 and 1876) seems to 

 re put forward the same view in the main as that represented by Quincke 

 Lehmann himself is also inclined to an opinion of this kind, in the chapter 

 ited upon the jellies, even though he supposes they have a spongy instead 

 of a frothy framework. It is not quite intelligible to me, however, how with 

 such views with regard to the physical nature of jellies, he can interpret in 

 a following chapter "the phenomena of swelling as due to chemical combina- 

 tions " (that is to say, of the body that swells) "with the solvent medium " 



